Is there anything I shouldn't do before a CT scan?

Do not eat solid foods or drink certain liquids for 2 to 4 hours before your CT scan if your doctor or facility requires contrast dye.

What Not to Do

• Do not eat heavy meals or solid foods: If you are having a scan with contrast dye (especially of the abdomen or pelvis), avoid solid foods for 2 to 6 hours before the test to prevent nausea and clear your digestive tract for better images.
• Do not wear metal: Avoid wearing jewelry, hairpins, eyeglasses, dentures, hearing aids, or clothing with metal zippers, snaps, or underwires, as metal interferes with the X-ray images.
• Do not hide medical history or allergies: Do not forget to tell your care team if you are pregnant, breastfeeding, have asthma, or have allergies to iodine or contrast dye.
• Do not stop or start medications without asking: Do not skip your regular daily medications unless your doctor explicitly tells you to. Pay special attention to diabetes medications like metformin, which may need to be temporarily stopped.
• Do not consume caffeine or nicotine (if instructed): Certain specialized scans (such as a cardiac CTA) require you to avoid caffeine and nicotine products for 24 hours prior.

Always check the specific instructions provided by your UConn Health Radiology or the imaging facility performing your UPMC CT Scan Services, as preparation rules vary based on the type of scan.

The exact amount of water depends entirely on the specific type of CT scan you are having and your facility's protocol, ranging from no restrictions to drinking 2 to 4 glasses (16 to 32 ounces) right before the test, or 6 to 8 glasses the day before.

General Water Guidelines by Scan Type

• Scans with IV Contrast or General Scans: Many facilities ask you to fast from food and large amounts of liquid for 2 to 4 hours before the scan, though small sips of water for medications are usually allowed.
• Pelvic or CT Urogram Scans: You may be instructed to drink about 16 to 32 ounces (2 to 4 glasses) of water 30 to 60 minutes before your appointment to keep your bladder full for better imaging.
• Abdominal Scans with Oral Contrast: You might be given a specific contrast liquid to drink over an hour or two rather than plain water, or water may be used as a neutral oral contrast.
• After the Scan: Drinking 6 to 8 glasses of water afterward is often encouraged to help flush any intravenous contrast dye out of your system.

Always defer to the written instructions provided by your specific imaging center or doctor, as protocols vary widely based on what part of your body is being scanned.

You should generally avoid wearing a bra with metal underwire or hooks if you are having a CT scan of your chest, abdomen, or pelvis.

What to Wear and Avoid

• Underwire bras: Metal underwire can create bright streaks or artifacts on the images, which can sometimes interfere with the radiologist's ability to read the scan clearly.
• Metal-free bras: Wireless sports bras or bralettes that contain no metal hooks, eyes, or underwires are often acceptable, but check with your imaging center first.
• Hospital gowns: Many imaging facilities will ask you to change into a hospital gown to ensure the scan area stays completely free of metal or plastic fasteners.
• Other metal items: Leave jewelry, belts, and wired undergarments at home or remove them before the test.

Whether you can urinate before a CT scan depends on the specific type of scan you are having.

General CT Scans

• Most scans (like head, chest, or routine abdomen/pelvis): You can usually empty your bladder whenever you need to before the scan. There is no need to hold your urine unless your clinic gave you special instructions.

Specialized Scans (like a CT Urogram or Bladder Scan)

• Full bladder required: For a Computerized Tomography (CT) Urogram, you may be asked to drink a large amount of water beforehand and not urinate until the procedure is finished.
• Why it matters: Holding your urine fills and expands your bladder, which helps the radiologist see the bladder walls and urinary tract clearly.

Always follow the precise preparation sheet provided by your imaging center or doctor.

You can typically resume your normal routine right away, but you should avoid taking certain diabetes medications like metformin for 48 hours if you received intravenous contrast dye and your doctor instructed you to do so.

Things to Avoid or Limit

• Do not ignore specific medication holds: If you take metformin (or similar diabetes drugs) and received IV contrast, check with your physician because you may need to pause these medications for 48 hours until kidney function is verified.
• Do not drive if sedated: If you were given a sedative or strong antihistamine for an allergy before the scan, do not drive until the medicine wears off.
• Do not skimp on fluids: Avoid staying dehydrated; you should drink plenty of water over the next 24 hours to help flush the contrast dye out of your system.

What You Can Do

• Eat and drink normally: You can go back to your regular diet right away unless your care team gave you different instructions.
• Resume activities: You can return to work, exercise, and daily routines immediately.
• Continue breastfeeding: It remains safe to nurse your child after receiving contrast material.